Note: This post includes comments on verses 34 & 35.
14. But Peter standing up with the eleven, lifted up his voice, and spoke to them: Ye men of Judea, and all you that dwell in Jerusalem, be this known to you, and with your ears receive my words.
Peter standing up, etc. Here, as in the Gospels, Peter is represented as the chief of the Apostles and head of the Church. What a change has come over him who before was so timid and weak! Now filled with the spirit of God, and with the gift of tongues on his lips, he fearlessly proclaims to all the miracle of Christ’s Resurrection.
34. For David ascended not into heaven; but he himself said: The Lord said to my Lord, sit thou on my right hand,
35. Until I make thy enemies thy footstool.
36. Therefore let all the house of Israel know most certainly, that God hath made both Lord and Christ, this same Jesus, whom you have crucified.
Having proved the Resurrection from Psalm 16, St. Peter now proves the Ascension from Psalm cix. As in the former case, so now, the words of the Psalmist were not verified in the person of David, and hence they must refer to Christ. This the Jewish Doctors did not deny.
The right hand means the place of power and honor, and indicates the place of our Lord’s humanity in heaven, which is above all creatures, next to God Himself. These words prove the divinity of Christ, because none other than a Divine Person could be said to send the Holy Ghost from the Father. St. Peter, therefore, first showed that Jesus was sent and approved by God; next that He was the promised Messiah; and finally that He was God Himself. His conclusion, then, is that *’ all the house of Israel ” should know that God has made Jesus Christ the Lord and Master of all things in the world.
37. Now when they had heard these things, they had compunction in their heart, and said to Peter, and to the rest of the apostles: What shall we do, men and brethren?
38. But Peter said to them : Do penance, and be baptized every one of you in the name of Jesus Christ, for the remission of your sins: and you shall receive the gift of the Holy Ghost.
39. For the promise is to you, and to your children, and to all that are far off, whomsoever the Lord our God shall call.
Moved by the sermon of St. Peter, the Jews conceived a real sorrow for their sins in putting Christ to death and rejecting the promised Messiah. They earnestly asked what they should do to be forgiven. Peter replied that they should first repent, do pennance and then be baptized in the name of Jesus Christ, i.e., make external profession of their faith in the person and religion of Christ. Faith in God, in the Holy Trinity, and in our Lord are necessary for salvation. See on John 17:3.
Some theologians have thought that in the early ages the sacrament of Baptism was sometimes administered by invoking the name of Jesus Christ only, but this is against the common teaching and tradition of the Church. The correct form of the sacrament is only that given in Matthew 28:19. St. Peter was not here giving the formula of Baptism, but merely describing the effects of the sacrament.
You shall receive the gift, etc. The effect of Baptism is to give sanctifying grace to the soul, which makes the soul the temple and dwelling place of the Holy Ghost and His gifts. The promise of the Holy Spirit is to all, both near and far, Jews and Gentiles, who are disposed to receive Him. Some understand this giving of the Holy Ghost to have been the sacrament of Confirmation which, in the early Church, was given with Baptism, or soon after it; but this is hardly probable.
40. And with very many other words did he testify and exhort them, saying: Save yourselves from this perverse generation.
St. Luke gives only a part of St. Peter’s discourse, in which he gave testimony regarding the life, miracles, death, and Resurrection of our Lord, This perverse generation refers to the unbelieving and unrepenting Jews who would not believe and be baptized.
41. They therefore that received his word, were baptized; and there were added in that day about three thousand souls.
Were baptized. St. Luke does not say by whom they were baptized, whether by St. Peter or the other Apostles; nor does he indicate the method or rite which was followed. More probably the Baptism was not administered by immersion, because water for so many was not plentiful in Jerusalem, and because there was hardly sufficient time to baptize so many by immersion in one day. We know, moreover, that Baptism was administered by infusion at a very early date (Didache, c. vii).